The latest forecast map from the National Hurricane Center shows Isaac zeroing in on landfall in Louisiana or the western Mississippi coast. The system still is a tropical storm, but the hurricane center's latest advisory says reconnaissance aircraft indicate it's getting stronger.

At 7 p.m. CDT, Isaac was about 295 miles (470 km) south-southeast of Mobile, Alabama, and about 230 miles (370 km) southeast of the mouth of the Mississippi River.

Its maximum sustained winds have increased to 70 mph (110 km/h) with higher gusts. Isaac is expected to strengthen and become a hurricane later tonight or early Tuesday. It's expected to continue strengthening until it makes landfall.

Tropical storm force winds continue to extend up to 205 miles (335 km) from the center of the storm.

Isaac is moving northwest at 10 mph (17 km/h). That general motion is expected to continue today with a gradual decrease in forward speed. The center of the storm will move over the eastern Gulf of Mexico tonight and be near the northern Gulf Coast by late Tuesday.

7 p.m. CDT Advisory

Winds: 70 mph

Pressure: 981 mb

Movement: NW at 10 mph

Coordinates: 26.7 N, 86.5 W

A hurricane warning is in effect for east of Morgan City, Louisiana, to the Alabama-Florida border. It includes New Orleans, coastal cities in Mississippi, and Mobile, Alabama. A hurricane warning means those conditions are expected somewhere within the area.

A hurricane watch is in effect from Intracoastal City to Morgan City, Louisiana. A tropical storm warning is in effect from the Alabama-Florida border to the Aucilla River and from Intracoastal City to Morgan City, Louisiana. A tropical storm watch is in effect east of Sabine Pass to west of Intracoastal City, Louisiana.

Tropical storm conditions are expected to reach the northern Gulf Coast in the warning area tonight, and hurricane conditions are expected on Tuesday.

Storm surge is expected to post a major threat to the northern Gulf Coast. If the peak surge occurs at high tide, southeast Louisiana and Mississippi could see a surge from 6 to 12 feet, Alabama could see 6 to 9 feet, and the Florida panhandle could see 3 to 6 feet.

Total rainfall amounts of 6 to 12 inches -- with maximum amounts of 18 inches -- are possible in southeastern Louisiana, southern Mississippi, southern Alabama and the extreme western Florida panhandle.

Tornadoes are possible along the northern Gulf Coast late tonight and tomorrow. Dangerous surf and rip current conditions will begin to affect the region tonight.